A North Korean soldier has defected to South Korea through the heavily militarised land border, telling Seoul military personnel that he had shot dead two officers, South Korean officials say.

"According to the defector, he shot dead his platoon leader and a company commander before crossing the border"

- Spokesperson,
Seoul's Joint Chiefs of Staff 

"Six gunshots were heard and our guards spotted a North Korean soldier crossing the military demarcation line," a spokesperson for Seoul's Joint Chiefs of Staff said after the incident on Saturday.

"Through loudspeakers, we confirmed he wanted to defect to the South and we led him to safety," the spokesperson said, adding the soldier was being held in protective custody.

"According to the defector, he shot dead his platoon leader and a company commander before crossing the border," he added.

A defence ministry official confirmed a North Korean had defected across the land border, saying that he was being questioned by the military.

South Korean soldiers in the area, on the western part of the inter-Korean border, were put on alert after the incident around 12:10pm local time (03:10 GMT).

There was no independent confirmation of any casualties, but Yonhap news agency cited an unidentified military official as saying two North Korean soldiers had been seen "lying on the ground".

There was no comment from Pyongyang.

Buffer zone

Defections across the Demilitarised Zone (DMZ), a buffer zone dividing the two Koreas, are rare as the 250km-long land border is heavily armed and tightly guarded.

Escaping tyranny in North Korea [Al Jazeera]

The last reported crossing by a North Korean soldier was in 2010, and previous instances in 2008 and 2002.

Once described by former US President Bill Clinton as "the scariest place on Earth", the DMZ was created after the 1950-1953 Korean War.

Hundreds of North Koreans flee each year across its northern border with China and most make their way to the South, with more than 20,000 having found refuge in the wealthy capitalist neighbour.

Most cite economic hardship and political persecution as the main reasons for leaving home.

The two Koreas are still technically at war since the Korean War ended only with a ceasefire, not a peace treaty.

The latest defection came at a sensitive time, with both Koreas trading accusations of provocative behaviour in the run up to the December 19 presidential election in the South.

Last month, Seoul's navy fired warning shots to turn back North Korean fishing vessels after a series of incursions over their disputed Yellow Sea border.

Source: Al Jazeera and agencies